This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C xc2xa7119 from an application entitled Stereoscopic Image Display Apparatus Using Micro Polarizer earlier filed in the Korean Industrial Property Office on Apr. 16, 1998, and there duly assigned Serial No. 98-13553 by that Office.
1. Field of the Invention
The present invention concerns a stereoscopic image display apparatus for displaying an image as a three dimensional image (3D image).
2. Background Art
It is known to use 3D video camera to record a 3D image which gives the effect of solidity or depth to an ordinarily plane image. The 3D image is usually produced by employing the visual effect obtained by a stereoscope, through which one may view photographs of objects not merely as plane representations, but with an appearance of solidity, and in relief. The stereoscope is essentially an instrument in which two photographs of the same object, taken from slightly different angles, are simultaneously presented, one to each eye. Each picture is focused by a separate lens, and the two lenses are inclined so as to shift the images toward each other and thus ensure the visual blending of the two images into one three dimensional image. The 3D images taken by the video camera are usually processed for display according to the NTSC (National Television System Committee or PAL (Phase Alteration by Line) standards.
The conventional 3D video signal processor used in the stereoscopic image display apparatus requires a large number of memory devices to perform the field doubling or multiplexing the video data of both lenses, thus increasing its production cost. Particularly, it is very difficult to separate the video data of each pixel of the horizontal line into the left and right eye (lens) data in the lenticular type 3D video signal processor.
FIGS. 1 and 2 illustrate the structure of a conventional 3D video signal processor used in an LCD display and the signal waveforms thereof. The conventional 3D video signal processor includes a video/sync signal separator 100 for separating a 3D video signal according to NTSC or PAL into a synchronizing signal Sync and an analog RGB video signal Avideo, an analog-to-digital (A/D) converter 110 for converting the analog video signal Avideo to a digital video signal Dvideo, a phase locked loop circuit PLL 120 for generating a clock signal CLK1 in response to the synchronizing signal Sync, first to fourth field memory devices 140 to 143 for storing the digital video signal Dvideo, first and second multiplexers 150 and 151 for blending the left and right video signals from the first to fourth field memory devices and performing polarity inversion on them to accommodate the characteristics of the LCD, a digital switch 160 for selectively outputting the blended video signal, a control signal generator 130 for generating various control signals, and a digital-to-analog (D/A) converter 170 for converting the digital video signal to an analog video signal. The operation of such conventional 3D video signal processor is as follows:
An analog 3D video signal according to NTSC or PAL is separated by the video/sync signal separator 100 to an analog video signal Avideo and a synchronizing signal Sync. The analog video signal Avideo is converted by the A/D converter 110 to a digital video signal Dvideo and stored into the first to fourth field memory devices 140 to 143. The synchronizing signal Sync is applied to the PLL 120, which generates a clock signal CLK1 of a predetermined frequency which is then supplied to the control signal generator 130. Control signal generator 130 generates the control signals required for each circuit. The control signals include a sampling clock signal CLK2 for the A/D converter 110, write/read (W/R) enable signals w1 to w4 and r1 to r4 for the first to fourth field memory devices 140 to 143, switching clock signals CLK3 and CLK4 for the first and second multiplexers 150 and 151, and a selection signal sel for the digital switch 160. According to the write enable signals of the control signal generator 130, the digital video signal Dvideo is divided into even, odd, left eye and right eye data stored respectively into the first to fourth memory devices 140 to 143. The output signals Dndr1, Dndl1, Dndr2, Dndl2 of the first to fourth field memory devices 140 to 143 are field doubled, whose waveforms are shown in FIG. 2.
The outputs of the first to fourth field memory devices 140 to 143 are properly delivered to the first and second multiplexers 150 and 151, as shown in FIG. 1, to blend them according to the switching clock signals CLK3, CLK4 and make the polarity inversion according to the characteristics of the LCD, thereby generating 3D video signals Dld1 and Dld2 of lenticular type. The digital switch 160 selectively allows the outputs of the multiplexers according to the selection signal sel of the control signal generator 130. If desired for a CRT display, a D/A converter 170 may be provided to obtain an analog 3D video signal of lenticular type.
However, such conventional 3D video signal processor of lenticular type requires the left and right eye data separated of each pixel of the horizontal line, which seriously complicate the circuit construction increasing the number of the memory devices to perform the field doubling and blending of the left and right eye data. This results in increase of the production cost.
Various methods and devices are known for providing three dimensional images as exemplified by the following patents incorporated herein by reference: U.S. Pat. No. 4,122,484 to Sing Liong Tan entitled Display Device For Three-dimensional Television; U.S. Pat. No. 4,562,463 to Lenny Lipton entitled Stereoscopic Television With Field Storage For Sequential Display Of Right And Left Images; U.S. Pat. No. 5,007,715 to Antonius G. H. Verhulst entitled Display And Pick-Up Device For Stereoscopic Picture Display; U.S. Pat. No. 5,537,144 to Sadeg M. Faris entitled Electro-Optical Display System For Visually Displaying Polarized Spatially Multiplexed Images Of 3-D Objects For Use In Stereoscopically Viewing The Same With High Image Quality And Resolution; U.S. Pat. No. 5,638,082 to Wolfgang Grimm entitled Vision Testing For Stereoscopic Viewing By A Test Person; and U.S. Pat. No. 5,844,711 to Sadeg M. Faris entitled Method And System For Producing Micropolariazation Panels For Use In Micropolarizing Spatially Multiplexed Images Of 3-D Objects During Stereoscopic Display Process.
It is an object of the present invention to provide a stereoscopic image display apparatus which is simplified to reduce the production cost and considerably improve the picture quality by employing a micropolarizer.
According to an embodiment of the present invention, a stereoscopic image display apparatus for displaying a 3D image on a screen of a display panel, comprises a 3D video signal processor for converting an analog 3D video signal to a digital 3D video signal, and a micropolarizer attached to the display panel. The micropolarizer is composed of a plurality of first polarizing regions having a first polarizing direction and a plurality of second polarizing regions having a second polarizing direction perpendicular to the first polarizing direction. The first and second polarizing regions are alternately arranged with each other in the form of a matrix. The 3D video signal processor further includes a video/sync signal separator for separating the analog 3D video signal into an analog video signal and a synchronizing signal, a clock signal generator for generating a clock signal with a frequency corresponding to the synchronizing signal, a control signal generator for generating various control signals in response to the clock signal, an A/D converter for converting the analog video signal to a digital video signal, a first memory device for storing the part of the digital video signal belonging to the odd field, a second memory device for storing the part of the digital video signal belong to the even field of the digital video signal, and a multiplexer for multiplexing the left and right eye video signals respectively generated from the first and second field memory devices to generate a 3D digital video signal. The vertical frequency of the output data of the first and second field memory devices is preferably twice that of the input data. Thus, the analog 3D video signal from a host is separated into an analog video signal and a synchronizing signal. The analog video signal is converted to a digital video signal, which is separated into even and odd line signals stored into the respective field memory devices. The video data stored in the field memory devices are separated into the left and right eye video data, which are delivered to the multiplexers to generate the digital 3D video data. The digital 3D video image is supplied to a LCD display panel which has a micropolarizer attached to the front of the display panel, wherein the micropolarizer is composed of a plurality of first polarizing regions having a first polarizing direction and a plurality of second polarizing regions having a second polarizing direction perpendicular to the first polarizing direction, the first and second polarizing regions being alternately arranged with each other in the form of a matrix. And a viewer utilizes a pair of polarizing eye glasses accommodated to the LCD display panel to see the screen displaying the 3D image. The eye glasses demultiplex the 3D image into the right and left images through right and left polarizing glasses, so that the user again multiplexes the right and left images to finally experience the 3D image.
The present invention will now described more specifically with reference to the drawings attached only by way of examples.